A preliminary economic assessment at Standard Lithium's South-West Arkansas lithium project foresees an after-tax net present value of US$1.97 billion at an 8% discount rate.

Internal rate of return is pegged at 32.1%, with a total capital expenditure estimate of US$870 million, with a 25% contingency. Operational expenditures are expected to be US$77.9 million per year.

Standard Lithium has updated its inferred resources to be 1,196,000 tonnes lithium carbonate equivalent.

The mine has a 20-year mine life with an expected production average of 30,000 tonnes per year of lithium hydroxide monohydrate, to be used in lithium-ion batteries.

Standard Lithium has commissioned its industrial scale extraction plant at German firm Lanxess' facility in southern Arkansas. The brine is pre-treated to remove hydrogen sulphide gas and hydrocarbons, and is then treated with LiSTR technology, which uses inorganic absorbent to selectively absorb lithium ions from the brine. This produces a concentrated lithium chloride solution.

The demonstration plant has been operating since May 2020, to be used as proof of concept and for feasibility studies. The technology reduces processing times from days to hours, Standard Lithium said.